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04 June 2011

Evolutionary psychology and high standards of scientific research

Since its official launch in the early 1990s, and its precursor sociobiology in the 1970s, evolutionary psychological research has been the repeated target of controversy. Dawkins, in his afterword of David Buss' Handbook of Evolutionary Psychology (2005), wondered whether EP really warrants this degree of controversy and scrutiny. At the 'high' end of the spectrum of scientific claims, we find controversial claims like the effectiveness of homeopathy or the existence of telepathy, at the low end of the spectrum, we find questions like the effects of alcohol on motor control, and it seems self-evident that the former type of claims need to be held to much higher standards than the latter. At what end of the spectrum does EP lie? To Dawkins "Evolutionary psychology is seen by its critics as out at the high hurdle end [in terms of the plausibility of its claims]--the telepathy end of the spectrum--while it is simultaneously seen by its practitioners as down at the plausible end of the spectrum" Dawkins (2005, 978) unambiguously sides with EP; he writes "Without a doubt, the evolutionary psychologists are right in this case. The central claim they are making is not an extraordinary one. It amounts to the exceedingly modest assertion that minds are on the same footing as bodies where Darwinian natural selection is concerned." This seems to capture the hard core of the evolutionary psychological research program quite well, and phrased in these generic terms, it does not sound at all uncontroversial.

Yet, the recent retraction of Kanazawa's paper on the alleged racial differences in perceived physical attractiveness, and the earlier controversy on Hauser's scientific misconduct have each sparked debates that do seem to question EP's most basic assumptions.

For example, when it became clear that Marc Hauser fabricated and manipulated his data, amongst others in his research on linguistic abilities in cottontop tamarins, the feminist philosophers ran the story "Evolutionary psychology fail: a sad story - the misconduct is one more datapoint to cause concern about EP in general (note that Hauser is indeed an evolutionary psychologist, as well as a comparative psychologist, but I heard comparably few voices stating that comparative psychology is in a dire state). Following the Kanazawa retraction, several people friendly to EP, such as the writers of the Cognition and Culture blog (of which I am a member), have issued public statements to distance themselves from Kanazawa's research. More than 60 prominent EP scholars have issued a statement that says that Kanazawa's methods are not representative of their field. The fact that, to the best of my knowledge, historians of early modern philosophy did not write a public statement saying that plagiarism is not the norm in their field when the Martin Stone case went public does seem to indicate to me that EP is still regarded as controversial.

I think we need to make a distinction between hard core and protective belt theories in EP. Whereas EP's hard core idea is uncontroversial, specific hypotheses that go under its banner often are controversial. Take, for instance, (and I'm here deliberately taking an example of bona fide EP), the 2007 study by Geoffrey Miller on the effects of the ovulatory cycle on lap dancers. Miller studied the menstrual cycle and tips received of 18 lap dancers, and found that women received higher tips when they were ovulating. Now, we need a lot of auxiliary assumptions next to the general claim that the human mind is a product of natural and sexual selection to accept the plausibility of this hypothesis, in particular that humans would be able to detect signs of estrus. In contrast to other primates, human women do not exhibit clear visible signs of estrus. Indeed, women without ovulatory calendars or fancy apps to track their body temperature etc. don't even know themselves that they are ovulating! It thus requires a considerable amount of evidence to claim that estrus was not lost during human evolution. I think that 18 women is simply too small a sample to warrant any strong conclusions to the contrary. Similarly, Kanazawa's earlier research on the alleged connection between intelligence and being a night owl, or the claim that engineers have more sons and nurses have more daughters are only remotely connected to the hard core of EP. In the engineers case, one would need accept that the Trivers–Willard hypothesis regarding parental ability to vary offspring sex ratio also applies to humans AND that Simon Baron-Cohen's theory on the male brain is correct. Nevertheless, given the successes of EP, I am inclined to agree with Ketelaar and Ellis that EP is still a progressive research program. We need to remain vigilant about individual EP claims, but we need not question the health of the research program as a whole when an individual claim turns out to be ill-founded or poorly researched.

The problem is that media coverage of EP findings does often make sweeping generalizations of what are, at best, tentative findings (the coverage on the lap dance study is a point in case). The following statement in the Cognition & Culture Blog clarifies this pernicious connection quite well "The fact is that, on the whole, the media have been very positive about evolutionary psychology, reporting a variety of tentative findings as ground-breaking discoveries and making cultural heroes of some of the most effective defenders of the approach. (...) The problem is that this success was based not so much on an interest for scientific progress and for a genuinely naturalistic understanding of human affairs, as on a taste for sweeping generalizations with hints of political and moral relevance, in particular about sexual relationships, violence, domination, and so on. The reputation of evolutionary psychology has greatly gained from this press coverage, with more students attracted, more jobs, and more research funding, but there is a price to benefitting from the kind of distorted and simplified image produced by the media."

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Evolutionary psychology and high standards of scientific research

Since its official launch in the early 1990s, and its precursor sociobiology in the 1970s, evolutionary psychological research has been the repeated target of controversy. Dawkins, in his afterword of David Buss' Handbook of Evolutionary Psychology (2005), wondered whether EP really warrants this degree of controversy and scrutiny. At the 'high' end of the spectrum of scientific claims, we find controversial claims like the effectiveness of homeopathy or the existence of telepathy, at the low end of the spectrum, we find questions like the effects of alcohol on motor control, and it seems self-evident that the former type of claims need to be held to much higher standards than the latter. At what end of the spectrum does EP lie? To Dawkins "Evolutionary psychology is seen by its critics as out at the high hurdle end [in terms of the plausibility of its claims]--the telepathy end of the spectrum--while it is simultaneously seen by its practitioners as down at the plausible end of the spectrum" Dawkins (2005, 978) unambiguously sides with EP; he writes "Without a doubt, the evolutionary psychologists are right in this case. The central claim they are making is not an extraordinary one. It amounts to the exceedingly modest assertion that minds are on the same footing as bodies where Darwinian natural selection is concerned." This seems to capture the hard core of the evolutionary psychological research program quite well, and phrased in these generic terms, it does not sound at all uncontroversial.

Yet, the recent retraction of Kanazawa's paper on the alleged racial differences in perceived physical attractiveness, and the earlier controversy on Hauser's scientific misconduct have each sparked debates that do seem to question EP's most basic assumptions.